Method of Layering Composite Sheets to Improve Armor Capabilities

ABSTRACT

According to one embodiment, an armor system comprises a plurality of polylithic composite armor panels. Each of the polylithic composite armor panels comprising a plurality of layers. The plurality of layers comprise at least two layers having a different Young&#39;s modulus. Each of the plurality of layers comprising a plurality of sheets. The plurality of sheets comprise one or more fibers. The plurality of sheets have one or more respective weave characteristics.

TECHNICAL FIELD

This invention relates generally to the field of armor systems and moreparticular to a layering of composite sheets to improve armorprotection.

BACKGROUND

Shape charges such as Explosively Formed Penetrators (EFPs) haveaccounted for a large number of combat casualties. Lethality of EFPscomes in part from the shape and arrangement of a concave copper cone,called the liner, which transforms into a forceful jet of fluidic metalwhich easily perforates armor. Despite focused efforts on armordevelopment, Mine Resistant Ambush Protected (MRAP) vehicles and otherarmored vehicles still cannot defend against these threats. Morerecently, armor solutions such as the FRAG Kit 5 have been used toprotect military vehicles such as Humvees. However, these armorsolutions typically weigh around 200 lb/ft². Since nearly all armyvehicles are thousands of pounds overweight, even without any additionalarmor protection solution, most of these approaches have provedimpractical.

SUMMARY OF THE DISCLOSURE

According to one embodiment, an armor system comprises a plurality ofpolylithic composite armor panels. Each of the polylithic compositearmor panels comprising a plurality of layers. The plurality of layerscomprise at least two layers having a different Young's modulus. Each ofthe plurality of layers comprising a plurality of sheets. The pluralityof sheets comprise one or more fibers. The plurality of sheets have oneor more respective weave characteristics.

The sheets and layers may be held together by at least one adhesiveagent. In some embodiments an adhesive may comprise a resin. In someembodiments, a sheet and/or a layer and/or an entire composite panel mayhave a considerable variation in resin concentration as compared toanother sheet and/or another layer and/or another composite panel. Insome embodiments, low resin concentrations may be used.

In some embodiments, composite panels may be polylithic compositepanels. In some embodiments, composite panels may be monolithiccomposite panels.

Some of the embodiments, as set forth above, have similar features forboth monolithic and/or polylithic panels. In some example embodiments, asheet comprised in a polylithic and/or a monolithic panel may compriseone or more fiber characteristics such as but not limited to fiber types(i.e., fibers made of different materials) and/or different fiberthickness.

However, according to some embodiments, a sheet comprised in apolylithic may have more than one weave characteristics and comprises atleast two or more directions of weave of fibers in a panel. In contrast,in some embodiments, a monolithic panel may have one or more weavecharacteristics of fibers in a panel, with the exception, of directionof weave. Accordingly, in some embodiments, monolithic panels may have auniform direction of weave of fibers in one panel. For example, amonolithic panel may have only one direction of weave of fibers in apanel.

Embodiments relating to weave characteristics and/or fibercharacteristics are described in further detail later in thespecification.

Some embodiments of the disclosure relate to polylithic armor systemsand polylithic armor panels. In certain embodiments, the disclosuredescribes an armor system comprising a plurality of polylithic compositepanels having at least two layers having a different Young's modulus.

In some embodiments, an armor system may comprise at least onepolylithic panel that comprise at least one layer comprised of thickerfibers located toward the front or outer side of the armor system and atleast one layer comprised of finer fibers located toward the back orinner side of the armor system.

In some embodiments a polylithic panel may comprise at least two layerscomprising sheets having a thicker weave on the top and a finer weave inback.

In some embodiments, a polylithic composite armor panel of an armorsystem may comprise at least two layers. In some embodiments, apolylithic composite armor panel of an armor system may comprise atleast three layers.

Some embodiments of the disclosure relate to monolithic armor systemsand monolithic armor panels. In some embodiments, an armor system maycomprise at least a first monolithic composite armor panel comprisinglayers having a thicker and more flexible weave mesh, the firstmonolithic panel located toward the outer side of the armor system andat least a second monolithic composite armor panel comprising layershaving a finer rigid weave mesh, the second monolithic panel locatedtoward the inner side of the armor system.

According to some embodiments, an armor system may be comprised oflayers of thin monolithic panels, the thin monolithic panels having athickness of less than or equal to 0.5″.

Teachings of certain embodiments relate to designing armor solutionsusing polylithic armor panels and/or using monolithic armor panels, toprotect vehicles and personnel from a variety of projectile devicesincluding but not limited to shape charges, EFP's, IEDs, ballisticdevices and hypervelocity impacts.

According to some embodiments, having a more flexible composite paneltoward the outer side of an armor system may provide an ability to bendor flex backwards slightly following an impact thereby causing a longerdwell time. Increasing the impact time may advantageously decrease theamount of force exerted by a projectile upon an armor panel at any givenpoint of time.

Flexibility of an armor panel may be controlled in part by the nature offibers, thickness of fibers, directionality of weave and/or mesh size asdescribed in certain embodiments. A very flexible panel may not be ableto sustain a very larger impact force. Also over flexing may cause adeformation of the armor and injure occupants on the inner side.Accordingly, teachings recognize that a balance between hardness of apanel and flexibility of a panel may provide the best ballisticprotection.

Certain embodiments recognize optimal use of delamination, i.e. peelingaway of a sheet from an adjacent sheet, to dissipate energy of anincoming projectile. Teachings of certain embodiments recognizeimproving energy absorption of an armor system through physicallybreaking glass threads. For example, certain embodiments recognize thatan armor system having sheets with a finer mesh has more bonds that mustbe broken. In another example, certain embodiments recognize that anarmor system having sheets with more complex weave directionality (e.g.,a [0°/+45°/−45°/90°]s weave), the presence of a larger number of anglesin the sheets increase the energy absorbing capacity of the armorsystem.

Certain embodiments of the invention may provide one or more technicaladvantages. A technical advantage of one embodiment may include thecapability to increase the dwell time of a projectile thereby reducingthe force exerted force by a projectile device. A technical advantage ofone embodiment may include the capability to change the trajectory of aprojectile device. A technical advantage of one embodiment may alsoinclude the capability to increase impact time. A technical advantage ofone embodiment may also include the capability to lowering the forceexerted on one or more armor layers of an armor system. A technicaladvantage of one embodiment may also include the capability to decreasethe overall impact of a projectile.

According to some embodiments, armor systems having layers of differentcomposite panel compositions as set forth above may results in slowingthe penetrating tip located on the front of an EFP such that rearportions (or particles) of the EFP re-collide with front portion. Asrear EFP particles pushes forward on the front part the penetrating tipof an EFP gets pushed towards the sides and the front of the EFP becomesflattened. This significantly reduces the missile shape reformationability of an EFP which is responsible for its superior penetratingability. Accordingly, a technical advantage of one embodiment may alsoinclude the capability to decrease the shape change ability of aprojectile.

Further technical advantages of particular embodiments of the presentdisclosure may include an armor system that is lighter weight thanconventional armor. A lightweight armor system of the present disclosuremay be capable of protecting against a similar threat as a heavierconventional armor system. Yet another technical advantage of oneembodiment may be a relatively low cost solution to provide protectionagainst a variety of projectiles and high velocity impacts. Inparticular, armor systems comprising polylithic composite panels ormonolithic composite panels in accordance with the present disclosuremay protect against an shape charge such as an EFP, other explosivedevices such as IED's, other projectile threats, bullets, ballisticthreats and/or forms of hypervelocity impact.

Various embodiments of the invention may include none, some, or all ofthe above technical advantages. One or more other technical advantagesmay be readily apparent to one skilled in the art from the figures,descriptions, and claims included herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A shows an armor system having a plurality of polylithic compositearmor panels, according to one example embodiment;

FIG. 1B shows a cross-section of one polylithic composite armor panel ofFIG. 1A and depicts a plurality of layers comprised in one polylithiccomposite armor panel, according to one example embodiment;

FIG. 1C shows an enlarged view of one layer as shown in FIG. 1B andshows each layer further comprised of a plurality of sheets, accordingto one example embodiment;

FIG. 1D shows an enlarged cross-sectional view of a layer as shown inFIG. 1C depicting a plurality of sheets and showing a plurality offibers comprised in the sheets, according to one example embodiment;

FIGS. 2A, 2B and 2C depict fineness of weaves of example sheets whereFIG. 2A shows an example thick weave, FIG. 2B shows an example mediumweave and FIG. 2C shows an example fine weave, according to one exampleembodiment;

FIG. 3A shows an enlarged view of an example polylithic panel having atleast two layers, the top layer having thicker weaves and the bottomlayer having finer weaves, according to one example embodiment;

FIG. 3B shows an enlarged view of an example polylithic panel having atleast three layers, the top layer having thicker weaves, the middlelayer having medium weaves and the bottom layer having finer weaves,according to one example embodiment;

FIG. 3C shows an enlarged cross-sectional view of an example polylithicpanel having at least two layers, the top layer having sheets comprisedof thicker fibers and the bottom layer having sheets comprised of finerfibers, according to one example embodiment;

FIG. 4 depicts an armor system having polylithic armor panel layers,wherein at least two layers have a different Young's modulus, accordingto one example embodiment;

FIG. 5A shows an armor system having a plurality of monolithic compositearmor panels, according to one example embodiment;

FIG. 5B shows a cross-section of one monolithic composite armor panel ofFIG. 5A and depicts a plurality of layers comprised in one monolithiccomposite armor panel, according to one example embodiment;

FIG. 5C shows an enlarged view of one layer as shown in FIG. 5B andshows each layer further comprised of a plurality of sheets, accordingto one example embodiment;

FIG. 5D shows an enlarged cross-sectional view of a layer of FIG. 5Cshowing a plurality of sheets and depicts each sheet comprised of aplurality of fibers, according to one example embodiment;

FIG. 6A shows an enlarged view of a monolithic panel having at leastthree layers comprising sheets having thicker flexible weaves, accordingto one example embodiment;

FIG. 6B shows an enlarged view of a monolithic panel having at leastthree layers comprising sheets having finer rigid weaves, according toone example embodiment;

FIG. 6C shows an enlarged cross-sectional view of an example monolithicarmor system comprised of at least two monolithic panels, a firstmonolithic panels as in FIG. 6A located on the outer side of the armorsystem and a second monolithic panel as in FIG. 6B located on the innerside of the armor system, according to one example embodiment;

FIG. 7 depicts a vehicle comprising an armor system, polylithic ormonolithic, of the disclosure, in accordance with one exampleembodiment;

FIGS. 8A and 8B show an exemplary path of an explosively formedpenetrator (EFP) through a prior art armor system not having layeredcomposites as taught in the present embodiments, wherein, FIG. 8Adepicts an example shallow-disk shaped EFP making contact with a firstlayer of armor located on an outer side of the prior art armor systemand FIG. 8B depicts the EFP now formed into a missile-shaped structureas it penetrates through layers of prior art armor; and

FIGS. 9A, 9B and 9C illustrate an exemplary path of an explosivelyformed penetrator (EFP) through one embodiment of a layered composite(monolithic or polylithic) armor system of the disclosure wherein FIG.9A depicts an example shallow-disk shaped EFP contacting an outer sideof the armor system; FIG. 9B depicts the EFP as it penetrates through afirst layer of armor which flexes, slows the EFP, flattens thesurface-tip of the EFP and its shape-change ability; and FIG. 9Cillustrates the EFP as it penetrates through a second layer of armorwhich further flexes additionally slowing the impact, flattening thesurface tip and reducing shape change ability of the EFP, according toone example embodiment.

DETAILED DESCRIPTION OF THE DISCLOSURE

It should be understood at the outset that, although exampleimplementations of embodiments of the invention are illustrated below,the present invention may be implemented using any number of techniques,whether currently known or not. The present invention should in no waybe limited to the example implementations, drawings, and techniquesillustrated below. Additionally, the drawings are not necessarily drawnto scale. In some embodiments, like numbers in the drawings may refer tolike parts.

Teachings of certain embodiments recognize that armor systems may beused to provide protection against and/or reduce impact of variousprojectiles such as but not limited to shaped charges, EFP's, IEDs,ballistic devices, other explosives and hypervelocity impacts. Armorsystems of the disclosure may be used in conjunction with any vehicle,such as but not limited to, military vehicles, convoy vehicles and/orpersonnel carriers and may be useful to protect personnel and equipmentin war zones.

On the battlefield, shape charges such as explosively formed penetrators(EFPs), also known as explosively formed projectiles, pose seriousthreat to equipment and personnel. EFPs and other shape charges may havethe ability to pierce through the armor of a vehicle and injure or killthe occupants inside.

Various configurations of shape charges and EFPs have been developed andseveral are capable of penetrating extremely thick and heavy armor.Therefore, merely adding more armor layers to protect against a shapecharge may result in a vehicle that is overweight and less effective onthe battlefield. In accordance with a particular embodiment of thepresent disclosure, a lightweight armor system may be capable ofstopping a projectile or significantly reducing its destructivecapability.

While not wishing to be bound to any particular theory, the presentsection provides a brief description of how high energy explosives andshape charges may achieve their lethality. High explosives may beextremely powerful because of their ability to rapidly release energy inthe form of heat and pressurized gas. The extremely fast rate at whichthis energy may be discharged gives a high explosive its strength. Rapiddischarge of a large amount of energy into a small space may generateshock waves. For example, rapidly released energy may compressneighboring air or surrounding material that further increase itsvelocity. The compressed air may then rapidly propagate outward andcreate a shock wave.

When a high explosive is detonated, an explosion may begin at a smallportion at the edge of the explosive. This explosion may create a shockwave that may propagate through the rest of the explosive. When thisshock wave comes in contact with a portion of the high explosive thathas not yet exploded the shock wave detonates the unexploded explosive.Thus, the additional explosion causes the shock wave to increase invelocity.

By exploiting the properties of a high explosive, in conjunction withcertain geometric configurations, a more powerful and more focused blastmay be accomplished. Shape charges utilize properties of high explosivesand a conical geometric shape, lined with a metal liner, to achieve anexplosion that can reshape material from the metal liner into apenetrating configuration at the same time accelerating it by a highenergy explosion.

Inertial forces of a material (e.g., metal from a metal liner) that arebeing propelled by an explosion from rest to a hypervelocity may affectthe molecular structure of the material. A hypervelocity may be avelocity of over 6,700 miles per hour. Acceleration from rest to ahypervelocity generates extremely high inertial forces. These inertialforces may be significantly greater than the molecular forces holdingthe particular material together. As a result, the material may changeits form and may convert from a solid to a liquid with the dominatinginertial forces guiding the flow of the material.

EFPs and other shape charges use these principles while unleashing theirexplosive power. A shaped charge may be able to pierce a thickness ofsteel armor equal to six-times its diameter.

When a shape charge is detonated a shock wave that detonates the chargereaches the tip of its metal liner. The liner tip may accelerate forwarddue to inertial forces and reach a hypervelocity changing the solidmetal into a fluid. As the shock wave pushes the liner metal fluidtowards center and since there is already metal occupying the center,the metal gets pushed out in two directions, some of the metal getsthrust in the direction of motion and becomes part of the jet or thepenetrating portion of the shaped charge, while the rest of the metalgets pushed back towards the explosive and becomes part of the slug, theslow bulky portion of the shaped charge.

The remaining part of the conical liner may take the shape of a flatsheet and the shock wave may then impart additional momentum to the flatsheet giving it a final solid push. The shaped charge finally detachesfrom its casing.

The fluid metal has a varying velocity with length velocity decreasingfarther down. For example, a jet tip of the fluid metal may be travelingmuch faster than a slug. The result may be an ultra-fine long penetratortraveling at an extremely high speed which may go through armor with athickness of about six times the diameter of the charge. In accordancewith one embodiment of the present disclosure, the speed of the tip of ashape charge may be substantially decreased by an air gap embeddedwithin an armor system of the disclosure.

However, shaped charges are not as effective and efficient to piercearmor from a distance, since a jet of fluid material can continue tostretch and will eventually break apart before it contacts a distanttarget.

An EFP is a specific type of shaped charge designed to pierce armor froma distance. A wide range of EFPs have been designed depending on thedesired effect. An EFP structure may provide a distinct aerodynamicadvantage over shaped charges. EFPs are typically shaped assemi-spherical dishes (rather than conical shapes as described above)that may be covered by a metal liner. The metal liner may be copper, orany other suitable metal that behaves similar to a fluid when subjectedto extremely high inertial forces.

By having a more shallow dish shape an EFP jet does not become quite asconcentrated as a shape charge jet described in sections above. Often anEFP metal becomes a single slug rather than a separate slug and jet. Aminor jet may be present near the tip, but for the most part, the slugdoes not have a defined shape. EFPs typically have a larger slug thatstays together better, but may have lower penetration attributes. Forexample, an EFP may be able to pierce a thickness of steel armor equalto the charge diameter. However, an EFP liner may be concentratedtogether such that the metal does not break apart before it reaches itstarget, making it efficient to strike distant targets.

As set forth earlier, geometry of the curvature of the liner beforedetonation may control the shape an EFP changes into after detonation.Particular shapes may be found to provide optimum aerodynamic andpenetration attributes. The shape of an EFP may be important to itsability to penetrate. An EFP with a smaller surface area may penetrateeasier. This may be the result of the higher stress that the EFP impartsover a smaller surface area of the armor it is penetrating. This mayresult in greater penetration. In accordance with one embodiment of thepresent disclosure, surface area of the tip of an EFP may be increasedby an air gap embedded within an armor system.

An EFP may travel at hypervelocity regimes over 6,700 miles per hour. Ashock wave that accelerates the metal liner to these types of velocitiesmay cause the metal liner of an EFP to behave as if it were a fluid.Fluid effects caused by the inertial forces generated by the explosionmay in part contribute to the EFPs ability to penetrate.

As the fluid from an EFP tip penetrates armor, the armor may exert adrag force upon the tip of the EFP. However, instead of transmittingthis force throughout the entire EFP, as would occur if the EFP were asolid, the tip portion of the EFP that is subjected to the drag force,may fall away from the sides of a hole being created in the armor. Thus,instead of slowing down the entire EFP, only a small portion of the EFPmay experience drag from the armor while the rest of the EFP maintainsits velocity as it travels through the hole in the armor.

Additionally, as the portion of the metal tip gets dragged backwards bythe armor, the EFP may reshape itself into a better penetrator. This mayresult when the edges of the EFP may be somewhat consumed as they arepushed to the rear of the EFP reshaping the EFP to become a thinner andmore effective penetrator. For example, material from EFPs may bereshaped into a missile shape. The EFP, due to this reshaped form,effectively slides through the hole formed in the armor, as opposed tohaving large friction forces from the armor slow the entire EFP.Accordingly, an EFP effectively lubricates the armor walls through whichit is penetrating and despite its poor initial shape, is effectivelyable to reshape and bore through thick armor. In some embodiments, anarmor system having layered polylithic composite panels and/or havinglayered mololithic composite panels, according to some embodiments ofthe disclosure, may slow the surface tip of an EFP (by contact withcertain configurations and orders of polylithic layers and/or panels)causing the rear portions of the EFP to collide into the slower tipportion, which may significantly reduce the reshaping ability of an EFP.

In addition, an EFP during its hypervelocity flight may split into aseries of metal blobs or metal particles comprising leaders that aresmaller, but travel faster and slugs which may be slower and bulkier.Several leader particles such as a primary leader and a secondary leaderand several slugs such as a primary slug and a secondary slug may bepresent. A good EFP normally has all these metal particles well alignedwith out a large pitch or yaw. Accordingly, an armor to protect fromsuch an attack must be capable of withstanding multiple impacts. In someembodiments, configurations and arrangements of the layered compositesheets, polylithic or monolithic, as set forth in certain embodiments,slow down the initial EFP particles thereby causing later EFP particlesto crash into the slowed initial EFP particle rather than into an armorlayer. Accordingly, embodiments of the present disclosure provide acapability for changing the trajectory of an EFP (or other hypervelocityimpact) by causing the particles to misalign.

Much of the lethal damage from an EFP is due to the behind armor effects(BAE). When an EFP penetrates armor, it may launch spall into thevehicle. Spall refers to the fragments of armor that the EFP may causeto break off and accelerate into the interior of the vehicle. Thismaterial may be extremely hot and may be moving at an extremely highvelocity. As a result, these armor fragments may hit nearly everythingwithin the personnel compartment of the vehicle and may cause extremedamage to the vehicle and equipment inside and injury or death to anyoccupants.

Damage from EFPs may also result from the overpressure blast that maysend highly compressed air outwards at an extremely high velocity. Theoverpressure alone may cause blindness, deafness, and death. The overalleffect of an EFP penetrating a vehicle may be similar to a fragmentationgrenade being detonated within the vehicle.

In accordance with one embodiment of the present disclosure, an armorsystem having layered polylithic composite panels and/or having layeredmonolithic composite panels, may be capable of significantly reducingdestructive capability of a shape charge, an EFP, a high explosive, aswell as any high velocity impact by slowing the speed of the respectiveprojectile device.

FIGS. 1A-9C show certain example embodiments of the disclosure relatingto one or more armor systems including polylithic armor system 150and/or monolithic armor system 150 m. However, teachings recognize thatother armor systems as described in the present specification may bemade and/or modified and used and the invention is not limited toembodiments shown by the drawings.

FIG. 1A-D shows certain embodiments of one armor system 150 comprising aplurality of polylithic armor panels 155 (also referred to layers ofarmor 155). As set forth earlier, a polylithic panel may comprisecomposite fibers having more than one direction of weave in a singlepanel. Additional details regarding polylithic panels according to oneor more embodiments of the disclosure are set forth in sections below.

FIG. 1A depicts armor system 150 having at least a plurality ofpolylithic armor panels 155 a, 155 b, 155 c and 155 n, according to oneexample embodiment. In other embodiments, additional or lesser number ofpolylithic armor layers (or polylithic armor panels) 155 may be presentin armor system 150. In non-limiting examples, an armor system 150 ofthe present disclosure may comprise two or more polylithic armor panels155.

As further depicted in FIG. 1A, an outer side 151 of armor system 150 ofthe disclosure may refer to a side of armor system 150 that receivesinitial impact of a projectile 100 and inner side 152 may refer to aside of armor system 150 that is farthest away from the initial impactsite of projectile 100.

Projectile 100 may be any high explosive device, such as but not limitedto a shape charge, an EFP, an IED, a landmine, a high energy explosive,a ballistic device and/or any hypervelocity impact. However, teachingsof certain embodiments recognize that armor systems of the disclosure,exemplified by 150 or 150 m (described later), may provide protection ormitigate the effects of these as well as other types of projectiles thatmay be operable to penetrate armor.

FIG. 1B shows a cross-section of one polylithic composite armor panel155, such as but not limited to 155 a of FIG. 1A. Polylithic compositearmor panel 155 is comprised of a plurality of layers 140, depicted as140 a, 140 b, 140 n, according to one example embodiment.

FIG. 1C shows an enlarged view of one layer 140 and shows each layer 140further comprised of a plurality of sheets 130 according to one exampleembodiment.

FIG. 1D shows an enlarged cross-sectional view of a layer 140 anddepicts a plurality of sheets 130, showing each sheet 130 comprised of aplurality of fibers 120 according to one example embodiment.

The following section describes certain embodiments relating tocomposition and assembly of polylithic composite armor panels 155 (asshown in FIGS. 1A-4).

In some embodiments, armor layers 155 may be comprised of compositefibers 120. Fibers 120 may be made of a variety of composite materials.Non limiting examples of composite materials that may comprise fibers120 include e-glass, s-glass, an aramid fiber (e.g., Kevlar), carbonnanotubes, carbon fibers, aluminum fibers and combinations thereof.

A composite armor panel 155 (and 156—described later) of the disclosuremay be made of composite materials, often abbreviated as composites.Composite materials may provide lower weight armor solutions as comparedto steel counterparts. Composites comprising two or more distinctmaterials may be made or structured in a vast number of ways. Thepresent disclosure is not limited in any way by the materials or methodsby which composites may be made.

According to some embodiments, fibers 120 of composite materials may bewoven together and/or sewn together to form fiber sheets 130. Wovensheets 130 may be layered or stacked upon each other with a glue laidout in between each sheet 130. Glue (e.g., a resin) may be used to bindwoven fibers 120 (i.e., sheets 130) together to form layers 140.

In some embodiments, for assembly of polylithic composite armor panels155, a plurality of layers 140 may be placed in a machine that applies alarge amount of heat and pressure which causes layers 140 to bindtogether solidly. This forms a solid composite polylithic armor panel155. A plurality of polylithic composite panels (e.g., 155 a, 155 b, 155c, 155 n) may be further layered over each other to form an armor system150 or an armor solution 150.

Teachings recognize that in certain embodiments, for polylithiccomposite armor panels, one or more sheets 130 comprised of fibers 120may not be identical. For example, in one embodiment, each sheet may becomprised of two or more different fiber and/or weave characteristics.In another example embodiment, each sheet may be comprised of fibers ofthe same material but may have different fiber thickness and/or weavecharacteristics (e.g., fineness of mesh and/or directions of theweaves).

Several features and characteristics of fibers 120 and the way in whichthey are woven into sheets may contribute to performance of armor system150. In some example embodiments, fibers 120 may be made from one ormore of a variety of materials. In some example embodiments, fibers 120may have various thicknesses d. In some embodiments, non-limitingexamples of fiber characteristics may include material of fiber, andfiber thickness.

Teachings of certain embodiments recognize that armor systems of thedisclosure comprised of sheets having different fiber characteristicsmay be used to assemble armor panels 155 having different projectileprotection abilities.

For example, in one embodiment, a sheet 130 woven or stitched usingthick fibers 120 may have a very different performance as compared to asheet 130 woven or stitched using very fine thin fibers 120 and/or asheet 130 woven or stitched using medium thickness fibers 120.

The way in which fibers are woven may be referred to as weavecharacteristics which may also vary the performance and qualities of asheet 130 or an armor panel 155 composed thereof. Weave characteristicsmay comprise one or more of the following non-limiting exemplary factorssuch as direction of weave, fineness of mesh, type of weave, and patternof weave.

Teachings of certain embodiments recognize that armor systems 150 of thedisclosure comprised of sheets 130 having different weavecharacteristics may be used to assemble polylithic armor panels 155having different projectile protection abilities.

In some embodiments, a polylithic composite armor layer 155 may have oneor more different weave characteristics. For example, fibers 120 of apolylithic panel may have more than one direction of weave in a singlecomposite panel.

A direction of weave may be described the direction of a fiber in theweave. For example, a non-limiting example of a directions of weave is a[0°/90°] weave, which indicates that fibers 120 run in two directions, ahorizontal [0°] and a vertically [90°]. Another example direction ofweave is a quadraxial weave also referred to as a [0°/+45°/−45°/90°]sweave. This weave comprises fibers that run in four primary directions,hence “quadraxial”. The “s” is an abbreviation that refers to symmetric.The unabbreviated notation would be described weave. Directions as a[0°/+45°/−45°/90°/90°/−45°/45°/0°] of weaves are not limited to theexamples described here and weaves in many other directions as known toone of skill in the art may be used in various embodiments describedhere.

Certain embodiments recognize that in an armor system having sheets withmore complex weave directionality (e.g., a [0°/+45°/−45°/90°]s weave),the presence of a larger number of angles in the sheets mayadvantageously increase the energy absorbing capacity of the armorsystem.

In some embodiments, teachings recognize that resin concentration maychange material properties of a composite. For example, use of moreresin may cause an armor panel to be harder and less flexible. Teachingsrecognize that in certain embodiments, combination of resinconcentration and/or fiber characteristics and/or weave characteristicsmay allow control of flexibility and hardness in composite armor panelsof the disclosure.

FIGS. 2A, 2B and 2C depict another weave characteristic, the fineness ofweave also sometimes called mesh size. FIG. 2A shows an example thickweave 111 a in an example sheet 130. In some embodiments, a thickerweave 111 a may have more gaps and/or a larger mesh size due to beingwoven more loosely. Accordingly, in some embodiments, sheet 130comprising thick weave 111 a (or larger mesh size) may be flexible andsoft. While a thick weave 111 a may not result in very strong sheets130, layers 140, panels 155 and/or portions thereof, thick weave 111 amay provide flexibility.

FIG. 2B shows another sheet 130 having an example medium weave 111 b (ormedium mesh size) and FIG. 2C shows sheet 130 having an example fineweave 111 c (or small mesh size), according to some example embodiments.In some embodiments, a fine weave 111 c may have very few or very smallgaps (mesh size) since fibers 120 may be woven more tightly. In someembodiments, a fine weave 111 c may have substantially no gaps (ultrafine mesh size). Accordingly, in some embodiments, sheet 130 comprisingfine weave 111 c may be rigid and strong. In some embodiments, a sheet130, a layer 140, a panel 155 and/or portions thereof comprising fineweave 111 c may provide strength to ward off a projectile 100.

One of skill in the art will recognize that the teachings are notlimited to the mesh sizes shown in FIGS. 2A-C and several otherintermediate and combination mesh sizes may be present. Also the patternof weave may change the size of the mesh as will fiber thickness andfiber type.

Teachings of certain embodiments recognize that flexibility of an armorpanel may be controlled in part by the nature of fibers, thickness offibers, directionality of weave and/or fineness of mesh (also calledmesh size).

For example, in one embodiment, a technical advantage of a layer orportion of a layer having a thick weave 111 a to an armor panel 155 mayinclude the capability to flex in response to a projectile 100 therebyincreasing the dwell time of projectile 100 and reducing the forceexerted force by the projectile device.

However, a very flexible panel may not be able to sustain a very largerimpact force. Also over flexing may cause a deformation of the armor andinjure occupants on the inner side. Accordingly, teachings of certainembodiments recognize that a balance between hardness of a panel andflexibility of a panel may provide the best ballistic protection.

Certain embodiments recognize optimal use of delamination, i.e. peelingaway of a sheet from an adjacent sheet, to dissipate energy of anincoming projectile. Teachings of certain embodiments recognizeimproving energy absorption of an armor system through physicallybreaking glass threads. For example, certain embodiments recognize thatan armor system having sheets with a finer mesh has more bonds that mustbe broken.

Accordingly, FIG. 3A depicts a polylithic armor panel 155, according toone embodiment, having a first flexible layer 140 a comprising one ormore sheets 130 (not expressly depicted) having a thick weave 111 a (orlarge mesh size 111 a) which may be followed by a second layer 140 bcomprising one or more sheets 130 (not expressly depicted) having a fineweave 111 c (or small mesh size). In the embodiment described above,layer 140 a is located toward the outer side 151 of panel 155 andprovides a flexible layer which increases dwell time of projectile 100following initial impact. Layer 140 b is located toward the inner side152 of panel 155 and is the strong layer that may have capability toabsorb force exerted by projectile 100 on the layer above.

In some embodiments, combining the two effects of first increasing dwelltime and thus increasing impact time using an outer layer 140 a having alarger mesh 111 a followed by second, increasing the amount of forceabsorbed by using an inner layer 140 b having smaller mesh (comprised offine weave sheets) in response to a projectile 100 may together reducethe overall impact of projectile 100. For example, a technical advantageof embodiments having such a combination may include the capability tochange the trajectory of projectile 100.

FIG. 3B shows an enlarged view of an example polylithic panel 155 havingat least three layers 140 a, 140 b and 140 c. In this exampleembodiment, outer side layer 140 a may have a thicker weave 111 a, themiddle layer 140 b may have medium weaves 111 b and the inner side layer140 c may have finer weaves 111 c. Accordingly, first layer 140 a is aflexible layer followed by second layer 140 b with medium flexibilityand a third layer 140 c being a more strong and rigid layer.

FIG. 3C shows an enlarged cross-sectional view of an example polylithicpanel 155 having at least two layers, the outer layer 140 a having aplurality of sheets 130 comprised of thicker fibers 120 having athickness d₁ and the inner layer 140 b having a plurality of sheets 130comprised of finer fibers 120 having a thickness d₂, where d₁>d₂according to one example embodiment.

According to some embodiments, having a more flexible composite paneltoward the outer side of an armor system may provide an ability to bendor flex backwards slightly following an impact thereby causing a longerdwell time. Increasing the impact time may advantageously decrease theamount of force exerted by a projectile upon an armor panel at any givenpoint of time.

FIG. 4 depicts one example embodiment showing a panel 155 of anexemplary armor system 150 having multiple polylithic armor panel layers140, wherein at least two layers have a different Young's modulus.

Some embodiments of the disclosure relate to monolithic composite armorpanels and systems. Accordingly, FIG. 5A shows an example monolithicarmor system 150 m having a plurality of monolithic composite armorpanels, such as 156 a, 156 b, 156 n, according to one exampleembodiment. However, teachings recognize use of additional or lessernumber of monolithic armor layers (or armor panels) 156 in monolithicarmor system 150 m. In non-limiting examples, a monolithic armor system150 m of the present disclosure may comprise two or more layers ofmonolithic armor panels 156.

As shown in FIG. 5A, according to some embodiments, a monolithic armorsystem 150 m may comprise a plurality of monolithic composite armorpanels 156 layered from an outer side 151 to an inner side 152 ofmonolithic armor system 150 m.

FIG. 5B shows a cross-section of one example monolithic composite armorpanel 156 further comprising a plurality of layers 141.

FIG. 5C shows an enlarged view of one example layer 141 and shows eachlayer 141 may be further comprised of a plurality of sheets 131.

FIG. 5D shows an enlarged cross-sectional view of an example embodimentof layer 141 and depicts details of plurality of sheets 131 showingexample fibers 121 comprised in each sheet 131, according to one exampleembodiment.

A monolithic composite armor panel 155 may also comprise one or moreadhesive agents such as a resin.

Several features described above for embodiments relating to structureof polylithic armor panels 155 and systems 150 are similar to those ofmonolithic armor panels 156 and systems 150 m. However, as set forthabove, one distinguishing feature between a monolithic and a polylithiccomposition is that all sheets comprised in one monolithic panel haveone respective direction of weave. For example, in a non-limitingembodiment, all sheets comprised in one monolithic composite armor panelmay have a direction of weave (also called weave directionality) of[0°/90°] that may be used repeatedly to form a panel of a respectivethickness (e.g., 0.5 inches or 1 inch).

In some embodiments, since the weave directionality is constantthroughout a monolithic panel, the concentration of a resin in the panelis also substantially uniform.

Accordingly, in some embodiments, a sheet 131 as shown in FIG. 5D,comprised in a layer 14 of a monolithic panel 156 may comprise one ormore fiber types 121 (i.e., fibers made of different composite materialsas described in sections above for fibers 120). In some embodiments, asheet 131 may comprise fibers 121 having one or more different fiberthickness d. In some embodiments, a sheet 131 comprised in a monolithicpanel 156 may have one or more respective weave meshes having respectivethick fineness of mesh such as 111 a, medium fineness of mesh shown as111 b and fine mesh size 111 c as exemplified in FIGS. 2A-C.

FIG. 6A shows an enlarged view of monolithic panel 156 f having at leastthree layers 141 comprising sheets (not expressly depicted) havingthicker flexible weaves 111 a, according to one example embodiment.Accordingly 156 f may represent a flexible and/or softer monolithicpanel.

FIG. 6B shows an enlarged view of a monolithic panel 156 r having atleast three layers 141 comprising sheets (not expressly depicted) havingfiner mesh sizes 111 c (also referred to as rigid weaves), according toone example embodiment. Accordingly 156 r may represent a rigid and/orhard monolithic panel.

FIG. 6C shows an enlarged cross-sectional view of an example monolithicarmor system 150 m comprised of at least two monolithic panels 156 f and156 r as described in the paragraphs above. As depicted first monolithicpanels 156 f is located on outer side 151 of armor system 150 m andsecond monolithic panel 156 r is located on inner side 152 of armorsystem 150 m, according to one example embodiment.

According to some embodiments, an armor system may be comprised oflayers of thin monolithic panels, the thin monolithic panels having athickness of less than or equal to 0.5″.

As detailed earlier, having a more flexible composite panel toward theouter side of an armor system allows for flexing backwards slightlyfollowing an impact thereby causing a longer dwell time and increasingthe impact time may advantageously decrease the amount of force exertedby a projectile upon an armor panel at any given point of time.

FIG. 7 depicts a vehicle 20, such as but not limited to a militaryvehicle, that may be equipped with an armor system of the disclosuresuch as a polylithic armor system 150 or a monolithic armor system 150m, in accordance with certain example embodiments. An armor system 150may have a plurality of polylithic armor panels 155 as described. Anarmor system 150 m may have a plurality of monolithic armor panels 156as described. Armor system 150 or 150 m may be comprised on exterior ofvehicle 20. Occupants and equipment of vehicle 20 may be protected byarmor system 150 or 150 m from the penetrating effects of a projectile(not expressly depicted) which may target vehicle 20. Vehicle 20 may bemaneuverable and effective on a battlefield while it is equipped with anarmor system 150 or 150 m in accordance with embodiments of the presentdisclosure.

According to some embodiments, present armor systems such as 150 and/or150 m may be from about 1 mm to several inches in thickness. Other armorsystems that do not employ polylithic or monolithic composite panelcombinations as taught herein may be considerably heavier and thicker.For example, conventional armor systems, may be several inches thick. Inanother example, mere addition of two existing panels of armor to anexisting conventional armor system may add an additional weight of about20 lb/ft² or more depending on the type of armor material used. Ifvehicle 20 were equipped with any existing armor system or armor systemsolution, its maneuverability and effectiveness in protecting againstprojectiles 100 as described here may be diminished.

FIGS. 8A and 8B show an exemplary path of an example explosively formedpenetrator (EFP) 100 through a prior art armor system 150 b not havingeither the layered polylithic or layered monolithic composites, astaught in some of the present embodiments. FIG. 8A depicts an exampleshallow-disk shaped EFP 100 making contact with a first layer of armor155 a located on an outer side 151 of the prior art armor system 150 band FIG. 8B depicts the EFP 100 now formed into a missile-shapedstructure as it penetrates through all the layers of prior art armor,155 a, 155 b and 155 c. As depicted, EFP 100 is now reshaped into amissile shaped structure and slides through armor as it penetratesthrough layers of the prior art armor system 150 b. Since EFP 100 may befully constrained within armor material of armor system 150 b the EFPstays aligned on its trajectory through all the layers of the prior artarmor system 150 b.

FIGS. 9A, 9B and 9C illustrate an exemplary path of an example EFP 100through one embodiment of a layered composite armor system 150 or 150 m(monolithic or polylithic) of the disclosure wherein FIG. 9A depicts anexample shallow-disk shaped EFP 100 contacting an outer side 151 of thearmor system 150 or 150 m. FIG. 9B depicts the EFP as it penetratesthrough a first armor panel 155 a or 156 a which may, in someembodiments, flex and slow EFP 100.

In some embodiments, armor panels 155 a or 156 a may flatten thesurface-tip of EFP 100 and diminish its shape-change ability.

In some embodiments, armor panel 155 a or 156 a may slow the penetratingtip of projectile 100, thereby causing a collision of faster moving rearportions of the projectile 100, causing the projectile tip to gain anincreased surface area.

In some embodiments, the entire shape of a projectile may be changedfollowing contact with 150 or 150 m.

FIG. 9C illustrates path and shape of EFP 100 as it penetrates through asecond armor panel 155 b or 156 b which may in some embodiments, furtherflex and/or additionally slow impact of EFP 100. In some embodiments,additional slowing may further flatten the surface tip and additionallyreducing shape change ability of EFP 100, according to one exampleembodiment.

In some embodiments, subsequent encounters with two or more compositelayers arranged in accordance with various advantageous configurationsas set forth here may render EFP 100 unable or ineffective to penetratearmor layer 155 c or 156 c leaving the occupants and equipment behindprotective armor layer 155 c or 156 c protected. In some embodiments,one or more composite armor layers of the disclosure may increase theoverall energy absorption capacity of armor system 150 and/or 150 m.

Existing armor systems operate on the hard to soft concept and oftenhave hard metal armor panels for increased hardness. Teachings ofpresent embodiments recognize that flexibility of a fiber system causesmore substantial increases in protection relative to a metal system. Insome embodiments, this may be as fibers in tension may performsignificantly better than fibers being sheered.

Finely woven high resin panels, being strong and rigid, have been achoice in several existing armor solutions for providing protectionagainst projectiles. However, the present inventors have shown thatharder panels placed toward initial impact sites in an armor systemabsorb significantly less energy.

In contrast to present thoughts in the art, teachings of certainembodiments recognize the need for a fine tuning of hardness andflexibility of armor panel layers in an armor system. Accordingly, someembodiments relate to having a more flexible panel in the front and amore rigid panel in the back for energy absorption purposes. In someembodiments, a flexible front panel may increased dwell time and changethe trajectory and shape change properties of a projectile. In someembodiments, the more rigid back panels may reduce the exerted forceproviding increased protection. Teachings of certain embodimentsrecognize that merely having a flexible panel may not sustain a largerforce. Teachings of certain embodiments recognize and teach the balancebetween hardness and flexibility for optimal protection.

Composites of the disclosure may absorb energy from a projectile in anumber of ways. In some embodiments composites may absorb energy byfriction, by delamination, and/or by breaking of molecules of thecomposite fibers. Friction has been used for traditional armor systemsand is normally one of the most effective methods for bullets. However,present teachings recognize that for EFPs, due to their fluidic abilityto re-shape, friction alone may not be effective.

Present teachings recognize that in some embodiments, delamination mayrequire breaking of numerous bonds, e.g., of the resin glue, all alongthe length of a composite sheet 130. Accordingly, present teachings usein part delamination as an effective method of absorbing energy becauseit allows for a small impact zone to be absorbed over a large surfacearea.

Teachings also recognize the use of energy absorption occurs throughphysically breaking threads of fiber 120 or 121. Accordingly to someembodiments, teachings recognize that finer mesh have more bonds thatmust be broken. Accordingly, in some embodiments, composite polylithic(or monolithic) panels having a larger number of angles, such as a[0°/+45°/−45°/90°]s may be used advantageously for absorption of moreenergy.

Teachings of certain embodiments recognize the use of fiber thicknessand weaves may be fine tuned and located at positions within the armorsystem in relation to the direction and force of impact.

Modifications, additions, or omissions may be made to the systems andapparatuses described herein without departing from the scope of theinvention. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order. Additionally, operations of thesystems and apparatuses may be performed using any suitable logic. Asused in this document, “each” refers to each member of a set or eachmember of a subset of a set.

Although several embodiments have been illustrated and described indetail, it will be recognized that substitutions and alterations arepossible without departing from the spirit and scope of the presentinvention, as defined by the appended claims.

To aid the Patent Office, and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims to invokeparagraph 6 of 35 U.S.C. §112 as it exists on the date of filing hereofunless the words “means for” or “step for” are explicitly used in theparticular claim.

1. An armor system comprising: a plurality of polylithic composite armorpanels; each of the polylithic composite armor panels comprising aplurality of layers; the plurality of layers comprising at least twolayers having a different Young's modulus; each of the plurality oflayers comprising a plurality of sheets; the plurality of sheetscomprising one or more fibers; and the plurality of sheets having one ormore respective weave characteristics.
 2. The armor system of claim 1,wherein the one or more fibers have a type comprising an e-glass fiber,an s-glass fiber, an aramid fiber, a carbon nanotube, a carbon fiber, analuminum fibers and combinations thereof.
 3. The armor system of claim1, wherein the weave characteristic comprises a direction of weave, afineness of mesh, or a weave pattern.
 4. The armor system of claim 3,wherein the direction of weave comprises a [0°/90°] weave, a[0/+45°/−45°/90°]s a weave, and combinations thereof.
 5. The armorsystem of claim 3, wherein the fineness of mesh comprises a finely wovenmesh, a coarsely woven mesh, a thick mesh, a medium weave mesh, a thinmesh, intermediates or combinations thereof.
 6. The armor system ofclaim 1, further comprising a resin to bind at least two of the one ormore fibers or at least two of the plurality of sheets.
 7. The armorsystem of claim 1, wherein the plurality of polylithic composite armorpanels are layered from an outer side of the armor system to an innerside of the armor system, the outer side being the side of initialprojectile impact and the inner side being the side farthest away frominitial projectile impact.
 8. The armor system of claim 7, wherein eachof the polylithic composite armor panels comprises at least two layers.9. The armor system of claim 8, wherein at least a first layer of thetwo layers comprises sheets having a thicker weave, the first layerlocated toward the outer side of the armor system; and at least a secondlayer of the two layers comprises sheets having a finer weave, thesecond layer located toward the inner side of the armor system.
 10. Thearmor system of claim 1, wherein each of the polylithic composite armorpanels comprises at least three layers.
 11. The armor system of claim10, wherein: at least a first layer of the three layers comprises sheetshaving a thicker weave, the first layer located toward the outer side ofthe armor system; at least a second layer of the three layers comprisessheets having a medium weave, the second layer located toward a middleside of the armor system; and at least a third layer of the three layerscomprises sheets having a fine weave, the third layer located toward theinner side of the armor system.
 12. An armor system of claim 1,comprised in a vehicle.
 13. An armor system according to claim 1,operable to improve resistance to impact by a shape charge, anexplosively formed penetrator (EFP), an improvised explosive device(IED), a ballistic device or a hypervelocity impact.
 14. An armor systemcomprising: a plurality of polylithic composite armor panels; theplurality of polylithic composite armor panels layered from an outerside of the armor system to an inner side of the armor system, the outerside being located toward an initial projectile impact site and theinner side being located away from the initial projectile impact side;each of the polylithic composite armor panels comprising a plurality oflayers; each of the plurality of layers comprising a plurality ofsheets; the plurality of sheets comprising one or more fibers; theplurality of sheets having one or more respective weave directionalityand one or more respective weave meshes; the plurality of sheetscomprising one or more different fiber thickness; and at least one ofthe polylithic composite armor panels has at least one of the layerscomprising thicker fibers toward the outer side of the armor system andfiner fibers toward the inner side of the armor system.
 15. The armorsystem of claim 14, wherein each of the polylithic composite armorpanels comprises at least two layers.
 16. The armor system of claim 15,wherein: at least a first layer of the two layers comprises sheetshaving a thicker weave, the first layer located toward the outer side ofthe armor system; and at least a second layer of the two layerscomprises sheets having a finer weave, the second layer located towardthe inner side of the armor system.
 17. The armor system of claim 14,wherein each of the polylithic composite armor panels comprises at leastthree layers.
 18. The armor system of claim 17, wherein: at least afirst layer of the three layers comprises sheets having a thicker weave,the first layer located toward the outer side of the armor system; atleast a second layer of the three layers comprises sheets having amedium weave, the second layer located toward a middle side of the armorsystem; and at least a third layer of the three layers comprises sheetshaving a fine weave, the third layer located toward the inner side ofthe armor system.
 19. An armor system comprising: a plurality ofmonolithic composite armor panels; the plurality of monolithic compositearmor panels layered from an outer side of the armor system to an innerside of the armor system, the outer side being located toward an initialprojectile impact site and the inner side being located away from theinitial projectile impact side; each of the monolithic composite armorpanels comprising a plurality of layers; each of the plurality of layerscomprising a plurality of sheets; the plurality of sheets comprising oneor more fibers having one or more different fiber characteristics; theplurality of sheets having at least one respective weave directionality;the plurality of sheets having one or more respective weave meshes; andat least one of the monolithic composite armor panels having a thickerflexible weave mesh located toward the outer side of the armor system;and at least a second of the monolithic composite armor panels layerscomprising layers having a finer rigid weave mesh located toward theinner side of the armor system.
 20. The armor system of claim 19,wherein the monolithic panel has a thickness of less than or equal to0.5″.